Decline of Species That Pollinate Poses a Threat to Global Food Supply, Report Warns

Beekeepers using a smoker to calm colonies before transferring them to another crop near Columbia Falls, Me. Plants that depend on pollination make up 35 percent of global crop production volume with a value of as much as $577 billion a year.

The birds and the bees need help. Also, the butterflies, moths, wasps, beetles and bats. Without an international effort, a new report warns, increasing numbers of species that promote the growth of hundreds of billions of dollars’ worth of food each year face extinction.

The first global assessment of the threats to creatures that pollinate the world’s plants was released by a group affiliated with the United Nations on Friday in Kuala Lumpur, Malaysia. The summary will be posted online Monday.

Pollinators, including some 20,000 species of wild bees, contribute to the growth of fruit, vegetables and many nuts, as well as flowering plants. Plants that depend on pollination make up 35 percent of global crop production volume with a value of as much as $577 billion a year. The agricultural system, for which pollinators play a key role, creates millions of jobs worldwide.

Many pollinator species are threatened with extinction, including some 16 percent of vertebrates like birds and bats, according to the document. Hummingbirds and some 2,000 avian species that feed on nectar spread pollen as they move from flower to flower. Extinction risk for insects is not as well defined, the report notes, but it warned of “high levels of threat” for some bees and butterflies, with at least 9 percent of bee and butterfly species at risk.

The causes of the pressure on these creatures intertwine: aggressive agricultural practices that grow crops on every available acreeliminate patches of wildflowers and cover crops that provide food for pollinators. Farming also exposes the creatures to pesticides, and bees are under attack from parasites and pathogens, as well.

Climate change has an effect, as well, especially in the case of bumblebees in North America and Europe, said Sir Robert Watson, vice chairman of the group and director of strategic development at the Tyndall Centre for Climate Change Research at the University of East Anglia.

A warming world changes the territories of plants and pollinators, and changes the plants’ time of flowering, as well, leading to a troubling question, posed by Dr. Watson: “Will the pollinators be there when the flowers need them?”

\The group issuing the report, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, is made up of 124 countries, including the United States, and was formed through the United Nations in 2012. It resembles in some ways the Intergovernmental Panel on Climate Change, with a focus on providing analysis and policy proposals to promote biodiversity.

The group did not conduct new research, but synthesized current studies and analysis to reach its conclusions. The assessment, developed with the help of 80 experts, does not take a conclusive position on two issues that environmental activists have focused on intensely.

The report states that the contribution of controversial chemicals known as neonicotinoids “is currently unresolved.” Recent research suggests that even when the pesticides are present at levels that do not have lethal effects on individual insects, concentrations in the hive may have long-term effects on colonies of wild and managed bees.

The passionate opposition to these pesticides from many environmental activists, however, “has almost hijacked the whole question of what’s causing the declines,” said Simon Potts, a co-chairman of the assessment and deputy director of the Centre for Agri-Environmental Research at Reading University. The report lays out many contributing factors beyond insecticides to the pressures on pollinators, and notes that they “can combine in their effects.”

The report also notes that the effects on pollinators of genetically modified organisms, including crops that are resistant to insects or tolerant of insecticides, is not settled. “That’s a very clear knowledge gap,” Dr. Potts said. “We’re brutally honest with the science.”

A scientist at Bayer, a producer of neonicotinoids, applauded the report. Dr. Christian Maus, global pollinator safety manager for the company and one of the experts who contributed to the report, said that it confirmed “the overwhelming majority of the scientific opinion” on pollinator health — “that this is a complex issue affected by many factors.”

Laurie Adams, executive director of the Pollinator Partnership, a group whose officials contributed expertise to the report, called the report a milestone that would “make a practical and effective contribution to finding solutions to pollinators challenges.”

The assessment is not structured to support advocacy, but to give governments, policy makers and organizations a sense of the current state of science and the options to address problems, the authors said.

“The messages here are clear,” Dr. Watson said. “If you want to protect pollinators, this is the suite of options you should consider — or, could consider.”